Equilibrium, kinetic and thermodynamic studies of adsorption of Pb(II) from aqueous solution onto Turkish kaolinite clay


Sari A., TÜZEN M., cıtak D., Soylak M.

JOURNAL OF HAZARDOUS MATERIALS, cilt.149, ss.283-291, 2007 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 149 Konu: 2
  • Basım Tarihi: 2007
  • Doi Numarası: 10.1016/j.jhazmat.2007.03.078
  • Dergi Adı: JOURNAL OF HAZARDOUS MATERIALS
  • Sayfa Sayıları: ss.283-291

Özet

The adsorption of Pb(II) onto Turkish (Bandirma region) kaolinite clay was examined in aqueous solution with respect to the pH, adsorbent dosage, contact time, and temperature. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms and both models fitted well. The monolayer adsorption capacity was found as 31.75 mg/g at pH 5 and 20 degrees C. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data. The mean free energy of adsorption (13.78 kJ/mol) indicated that the adsorption of Pb(II) onto kaolinite clay may be carried out via chemical ion-exchange mechanism. Thermodynamic parameters, free energy (Delta G degrees), enthalpy (Delta H degrees) and entropy (Delta S degrees) of adsorption were also calculated. These parameters showed that the adsorption of Pb(II) onto kaolinite clay was feasible, spontaneous and exothermic process in nature. Furthermore, the Lagergren-first-order, pseudo-second-order and the intraparticle diffusion models were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetics. (c) 2007 Elsevier B.V All rights reserved.